Automatic tongs



E. E. ECKSTEIN AUTOMATIC TONGS July 7, 1959 3 Sheets-Sheet 1 Filed Feb. .5, 1957 INVENTOR.

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United States Patent AUTOMATIC TONGS Ernest E. Eckstein, Elgin, Oreg. Application February 5, 1957, Serial No- 638,359 Claims. Cl. 294-110) This invention relates to what has been designated as automatic tongs. More particularly, it has reference to improvements in that class of material handling tongs typified by the device of my U.S. Patent Reissue No. 24,058, dated September 6, 1955.

Itis the principal object of this invention to provide automatic tongs of a much simplified character, and

adapted for use on the dipper stick of a crowd shovel or on a suspended boom as a means for the expeditious handling or loading of such objects as logs, beams and the like, or various other heavy objects of such charactor that they can be handled by means of tongs.

It is a further object of this invention to provide tongs for the above stated purposes that may be readily applied to and also released from the object handled, without use of any external means or power other than that afiorded through the hoisting, lowering, crowding, rei".

tracting or swinging motions normally incident to the use of the ordinary powered shovel with which it is associated.

It is a further object of this invention to provide automatic tongs that require no controls for application or release other than those provided to obtain the shovel operating motions, thus eliminating any and 2 11 requirements for valves, switches, air eompressors, hoses, valv electric wiring or hydraulic supp y l nes Still further objects and advantage Of: the invention reside in the details of construction and combination o Parts embodied by the. present ong and in thei mode of use, as will hereinafter be fully described.

In accomplishing the above mentionedand other ebiects of the invention, I have, provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein:

Fig. l is a side view of ashovel type loader showing the dipper stick thereof equipped with Fig. 2 is a perspective view of the internal mechanism of the present device and the paired tongs, with the mechanism enclosing housing shown only in phantom lines. V

Fig. 3 is a side view of the tongs and tong supporting linkage, and its enclosing and supporting housin the. lat.- ter having a sidewall portion broken away for better show ing of the enclosed mechanism.

Fig. 4 is a similar view, but showing the tong'supportautomatic ton ing linkage released or. disengaged from itsv latch or supporting arm.

Fig. 5 is an end view of the. tongs and supporting linkage in the log or load lifting setting.

Fig. 6 is a similar end view of the mechanism, and showing the tongs in open position.

Referring more in detail to the drawings:

In Fig. 1, I have shown a typical power operated shovel mechanism 10 mounted on crawler tracks and including a boom 11, equipped with the usual dipper stick 12. This stick 12 is supported at its outer end by a cable 13 that extends upwardly therefrom, over a fairleader sheave support the tongs in such relationship laterally spaced relationship,

14 at the outer end of the boom, and then to anysuitable powered operated cable winding means, not shown, which may be mounted on the turntable'platform '15 of the machine. By the usual controls provided in such machines, the turntable may be turned to swing the boom from side to side. Also, the boom is so supported that it can be raised or lowered 'as'required, and the dipper stick can be extended and retracted in the usual way.

The automatic tong mechanism embodied by the pres ent invention is carried at the outer end of the dipper Stick 12 and, in its present preferred form of construction, it comprises an elongated box-like frame or enclosing housing 20 that is rigidly fixed to the stick end as an extension thereof; It isshown in' Figs. 3 "and 4, that the housing 20 is secured at its innerend by bolts 21 to the outer endportion of the stick at a slightly upwardly inclined angle "relative thereto. Also, it is therein shown that the housing 20 is substantially square in crossesection and comprises oppositesidewalls 22 and 22; a top wall 23 and a bottom wall 24.

Formed on the inner end portion of the housing 20 is a transversely directed and downwardly extended log heeling plate 25 braced by a longitudinal web plate 26; this being used in some instances as an aid in controlling the placing ofthe log on a support as well understood in the art.

The paired tongs 30-30 herewith used are joined pivotally in crossed relationship by a pivotbolt 31. At their upper ends they are equipped with shackles 32-32 which are applied through an eyelet 33 formed at the lower end of a bolt 34 that is swivelly suspended from the base end of a U-shaped hanger link 36. The link '36 is swingingly suspended from a horizontal pivot shaft 37, extended transversely of the housing 20 between the swinging ends of a pair of laterally spaced parallel links 38-38; these links being disposed in planes that are parallel to the planes of the sidewalls of the housing and swingingly pivoted at their forward ends on a cross-shaft 39 that is fixed in the lower part of the forward end portion "of the housing.

The paired tongs 30-30 also are connected by chains 40-40 to cars 41 formed on opposite sidewalls of the housing 20; it being shown in Figs. 5 and 6 that the connection of the chains with the tongs is through cars 42 formed on the tongs below the tong connecting pivot bolt 31. Also, it is to be observed byreference to these same views, that when the paired links 38-38 are directed upwardly and rearwardly from shaft 39, as shown in Figs. 3 and 4, the link 36 and swivel bolt 34 then to the housing that they are unsupported by the chains 40-40 as indicated in Fig. 5, and the slack in the chains permits the tongs to close together. However, if these links 38-38 'are released and permitted to swing downwardly in the housing, as to the position of Fig. 4, the link 36 and swivel bolt 34 are lowered accordingly, thus lowering the tongs relative to the housing to such extent that the chains 40-40 become taut and elfect the opening ofthe tongs, as shown in Fig. 6. i 1

It is also shown, particularly in Figs. 2 and 3, that parallel arms 50-50, are mounted in the housing 20 in I rearwardly of the swinging 'endsof links 38-38, on a crossshaft- 51 extended between opposite sidewalls of the housing; these arms being joined rigidly in spaced, parallel relationship by a web plate 52.

At their swinging ends, the arms 50-50 are formed with recesses or notches 53, as seen best in Fig. 4, and the relationship of these arms to the cross shaft 37 carried by the links 38-38 is such that when the latter are swung upwardly from their position of Fig. 4 to the upwardly directed position of Fig. 3, the arms 50-50 will be swung upwardly and the cross-shaft 37 can be received in the arm notches 53 for support. Thus, in their supported position of Fig. 3, the pair of tongs will be held in that lifted position relative to the housing that results in a'substantial amount of slack in the chains 40-40 and permits the tongs to close together as for the pick-up of a log or other object between them.

Fixed on that side of the suspended link 36 that faces the arms 50-50, as well shown in Fig. 3, is a projecting lug 55; this being for a purpose presently explained.

Assuming that the present device is so constructed and applied to a dipper stick as herein illustrated, it is used for the handling of logs as follows: First, assuming that the device is moved to a position over a log and that the paired arms 5050 are disengaged from shaft 37 and that the linkage 3838 has been permitted to drop to the position in which it is shown in Fig. 4; this causes the paired tongs, by reason of their being supported by the chains 4040, to open apart as in Fig. 6. The device is then lowered by the boom stick and the tongs placed across the log. Then with continued lowering, the crossed tongs will engage with the log directly below the hinge pin 31 and the swinging linkage 3838 will then be pushed upwardly by reason of the swivel pin 34 and link 36. When the links 38-38 have been sufiiciently lifted, the cross-shaft 37 carried by their upwardly swinging ends, drops into the notches 53 at the outer ends of the arms 5050. The arms then support the links in this position. With this upward lifting of the linkage 38-38 the tongs 3030 are permitted to close together, and the teeth at the tong ends will engage with the log at opposite sides. Then, by an upward movement of the dipper stick, the tongs, now supported by the locked linkage, as in Figs. 2 and 3, bite into the log and it can be lifted, as in Fig. l, and carried to a place of disposal or loading. If it is desired to have the log heeled against plate 25, the tongs would be applied at. the proper place to effect this result.

To automatically release the tongs from the log after it has been moved and then lowered to a position of rest, it is only necessary that the operator slightly retract and then slightly extend the dipper stick in such way as to cause the jackknifing of the tongs and swivel linkage, as for example, to their dotted line positions of Fig. 3, thus to cause the lug 55 as formed on link 36 to engage the web plate 52 between the arms 5050 and unseat the notched ends of the arms from supporting engagement with cross-shaft 37. This releases the links and with the lifting of the boom and stick, the chains 40-40 become taut, and the tong teeth are pulled free of the logs as the tongs open. They are then lifted clear of the log and held suspended in this open position for application to the next log to be handled.

For the purpose of a better understanding of the following claims, that element comprised by the paired links 3838, joined at their outer ends by the cross-shaft 37 will be designated as the swinging link; the element comprised by the paired arms 5050, as mounted pivotally by cross-shaft 51 and rigidly joined in spaced relationship by the web plate 52, will be designated as the latch arm; and the linkage comprised by the shackles 32, 32, the swivel bolt 34 and U-shaped link 36 which mounts the swivel bolt therein, will be designated as the hanger link.

What I claim as new is:

1. A tong mechanism comprising a longitudinally elongated, box-like, steel frame structure mounted in fixed position on the outer end of a dipper stick, or the like, a pair of crossed and pivotally joined tongs, said tongs having upper ends extending above the point of pivotal joining and lower ends adapted to engage a log, a swinging link, a transversely disposed mounting means on the outer end of said frame, one end of said swinging link pivotally mounted on said mounting means, means pivotally connecting the upper ends of said tongs and the free end of said swinging link, a latch arm having one end thereof pivotally mounted and the other end free, means for pivotally mounting said latch arm on an axis transverse of the steel frame at the end thereof opposite said swinging link mounting means with said axis parallel to said swinging link mounting means, said latch arm being disposed in substantially the same plane as the swinging link, latch arm engaging means on the free end of said swinging link, means on the free end of the latch arm positioned to be releasably engageable with said latch arm engaging means, a flexible cable fixed at one end to the frame and at its other end to one of said tongs at a point outwardly from and below the point of pivotal joining, the length of said cable being shorter than the distance the tongs move downward with the downward movement of the swinging link whereby the tongs are caused to open when the swinging link moves downward, the combined length of the swinging link and the latch arm being greater than the distance between the latch aIm mounting means and the swinging link mounting means so that when the free ends thereof are engaged they are respectively upwardly inclined and the locking engagement of the latch arm engaging means with the means on the free end on the latch arm adapted to retain the swinging link in an upward position whereby the cable is ineffective and the tongs are permitted to close.

2. A tong mechanism as recited in claim 1 wherein said swinging link comprises paired laterally spaced and parallel members joined at their free ends by said latch arm engaging means, and said latch arm is adapted to extend through the arc of travel of said laterally spaced members when moved upwardly.

3. The tong mechanism of claim 1 including a hanger link pivotally secured to the free end of the swinging link, means connecting the upper ends of said tongs to said hanger link, a lug fixed to the hanger link and projecting therefrom toward the latch arm, said hanger link being adapted to be pivotally moved in an upwardly directed arc to a position whereby said lug engages with said latch arm and causes an upward movement of the latch arm to unseat the means on the free end thereof from engagement with said latch arm engaging means.

4. The mechanism of claim 3 wherein said latch arm comprises laterally spaced and parallel opposite side members, a web plate secured to and extending between the underside of the side members, and against which web plate said lug engages to effect the disengagement of the latch arm from said latch arm engaging means.

5. The mechanism of claim 4 wherein said frame is fixed to a dipper stick or the like as an extension thereof and wherein the axes on which the swinging link, the latch arm and the hanger link are mounted in said frame is positioned transversely thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,558,778 Bennington Oct. 27, 1925 

